Verse 3.16.4

तं चेदेतस्मिन्वयसि किंचिदुपतपेत्स ब्रूयात्प्राणा रुद्रा इदं मे माध्यंदिनंसवनं तृतीयसवनमनुसंतनुतेति माहं प्राणानांरुद्राणां मध्ये यज्ञो विलोप्सीयेत्युद्धैव तत एत्यगदो ह भवति ॥ ३.१६.४ ॥

taṃ cedetasminvayasi kiṃcidupatapetsa brūyātprāṇā rudrā idaṃ me mādhyaṃdinaṃsavanaṃ tṛtīyasavanamanusaṃtanuteti māhaṃ prāṇānāṃrudrāṇāṃ madhye yajño vilopsīyetyuddhaiva tata etyagado ha bhavati || 3.16.4 ||

4. If, within these next forty-four years of his life, he has some ailment, he should then say: ‘O Prāṇas, O Rudras, please extend my midday libation and join it to the third libation. As the sacrifice, may I not disappear among the Rudras, who are my prāṇas [i.e., who are like my life].’ [If he prays like this,] he gets rid of his ailment and becomes fully well.

Word-for-word explanation:

Cet, if; etasmin vayasi, within these [forty-four] years of his life; tam kiñcit upatapet, something troubles him; saḥ brūyāt, he will say; prāṇāḥ, O Prāṇas; rudrāḥ, O Rudras; idam me mādhyandinam savanam, this, my midday libation; tṛtīya savanam, to the third libation; anusantanuta iti, extend; mā aham, may I not; yajñaḥ, as the sacrifice; prāṇānām rudrāṇām madhye, in the midst of the prāṇas, who are the Rudras; vilopsīya iti, disappear; tataḥ ha eva ut-eti, he gets rid of that [ailment]; agadaḥ ha bhavati, [and] becomes well.

Commentary:

The idea behind this prayer is: ‘O Rudras, you are like my life. I am the sacrifice, and now the midday libation is going on. Will you please extend this libation so that I may do the third libation without a break [that is, may I live long enough to do the evening libation]? I am the sacrifice, and I don’t want the sacrifice to be stopped before it reaches the end. And I don’t want to be separated from the Rudras, who are like my life.’

If the afflicted person (who is the sacrifice) keeps praying like this, he will then get well and be fully fit again.